Biofilm-producing candida species causing oropharyngeal candidiasis in hiv patients attending sukraraj tropical and infectious diseases hospital in kathmandu, nepal

Abstract

Introduction: Oropharyngeal candidiasis are the commonest fungal infections among HIV-positive patients. The main objective of this study was to explore biofilm-producing Candida species causing oropharyngeal infections among HIV patients attending Sukraraj Tropical and Infectious Diseases Hospital (STIDH) in Kathmandu, Nepal. Methods: Oropharyngeal swabs were collected from the HIV-positive patients between July and December 2019. A total of 174 oropharyngeal swabs were cultured on Sabouraud Dextrose Agar (SDA). All samples were inoculated on SDA slants supplemented with chloramphenicol and underwent incubation at 37°C for 24–48 hours. Any visible growth reported was processed for the identification of the species. Candida species were differentiated based on the growth and colour of the isolates on CHROM agar candida. Biofilm production in Candida species was determined by the microtiter plate method (MPM). Antifungal susceptibility testing was performed using the disc diffusion method. Results: Among 174 oropharyngeal samples, 23.6% (n=41/174) of them had oropharyngeal infections and 36.6% of the oropharyngeal infections (15/41) had CD4 T-lymphocytes count below 200 cells/mm3 who were also active tobacco users (p<0.05). Among Candidial growth, 61% (25/41) were Candida albicans and 39% (16/41) were non-albicans. Of 41 Candida spp., 65% (27/41) were biofilm producers. An equal proportion of Candida albicans (4 isolates) and non-albicans (4 isolates) were strong biofilm producers. C. albicans isolates were sensitive towards clotrimazole (96%; 24/25) and fluconazole (92%; 23/25), whereas sensitivity towards ketoconazole was only 48% (12/25). Non-albicans Candida was highly sensitive to amphotericin-B (62.5%; 10/16) followed by clotrimazole (56.2%; 9/16). The biofilm-producing Candida isolates showed the highest resistivity (51.9%; 14/27) to ketoconazole and lowest (22.2%; 6/27) to clotrimazole. Conclusion: Oropharyngeal candidiasis is a common opportunistic infection among HIV-infected individuals. The majority of cases of oropharyngeal candidiasis are caused by biofilm producers Candida albicans and non-albicans Candida. Biofilm producers Candida were more resistant towards commonly used antifungal drugs.